JP7177828B2 - Masterbatch, Polycarbonate Resin Composition, Injection Foaming Molded Article and Method for Producing Same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a masterbatch of thermally expandable microcapsules, a polycarbonate-based resin composition, an injection-foamed molded article, and a method for producing the same, which can improve the appearance of an injection-foamed article of a polycarbonate-based resin composition.

Thermally decomposable chemical foaming agents such as sodium bicarbonate are often used for injection foam molding of resins. Thermally expandable microcapsules that expand and foam when heated are also used for resin injection foam molding. In general, from the viewpoint of dispersibility in the base resin and workability, it is possible to use a masterbatch containing 20 to 60% by weight of a chemical foaming agent or thermally expandable microcapsules in a thermoplastic resin or thermoplastic elastomer. many. For example, Patent Document 1 describes a blowing agent masterbatch containing an ethylene/α-olefin copolymer and a thermally decomposable blowing agent as main components. Patent Document 2 describes a masterbatch containing thermally expandable microcapsules, a carrier resin containing an olefin polymer, and a lubricant.

For injection foam molding of resin, there is also a method called physical foaming, in which a supercritical fluid such as carbon dioxide or nitrogen is directly impregnated into a molten resin in a cylinder of an injection molding machine to foam the resin. For example, in Patent Document 3, a resin composition having a sea-island structure in which a resin (A) constituting a sea phase and a resin (B) constituting an island layer are kneaded is melted and kneaded in an injection molding machine to form a molten state. It describes that a foam molded article is produced by injecting a supercritical fluid into a resin composition and performing injection molding.

JP 2013-142146 A JP 2017-082244 A JP 2015-151461 A

However, when a polycarbonate-based resin is foamed using the foaming agent masterbatch described in Patent Document 1, the heat-decomposing foaming agent such as sodium bicarbonate generates moisture and metal components when gas is generated. Decomposition is accelerated, and whitening occurs on the surface of the injection foamed product due to hydrolysis, resulting in poor appearance. When a polycarbonate-based resin is foamed using the thermally expandable microcapsule masterbatch described in Patent Document 2, the carrier resin contains an olefin polymer. There is a problem that whitening occurs due to the coating, resulting in a poor appearance. When a polycarbonate-based resin is foamed by physical foaming as described in Patent Document 3, whitening occurs due to the impregnation gas, resulting in poor appearance.

In order to solve the above-described conventional problems, the present invention provides a masterbatch of thermally expandable microcapsules capable of suppressing the occurrence of whitening and obtaining an injection foam molded article of a polycarbonate-based resin composition with good appearance. Provided are a polycarbonate-based resin composition, an injection foam molded article, and a method for producing the same.

The present invention is a masterbatch (C) containing a thermally expandable microcapsule (A) and a carrier resin composition (B), wherein the carrier resin composition (B) comprises a carrier resin (B1) and a plasticizer ( B2), wherein the carrier resin (B1) has a weight average molecular weight of 8,000 or more and 350,000 or less and is an acrylic resin that is solid at 20°C, the plasticizer (B2) is liquid at 20°C, and The carrier resin composition (B) has a weight average molecular weight of 1,000 or more and 20,000 or less, is substantially compatible with the polycarbonate resin, and has a shear viscosity of 1.0 Pa·s or more at 80° C.1. It relates to a masterbatch characterized by having a viscosity of 5×10 ⁶ Pa·s or less.

The masterbatch (C) can be suitably used for polycarbonate resins. The polycarbonate-based resin further includes a polyester-based resin, a polyester-polyether copolymer, an acrylonitrile-butadiene-styrene copolymer, an acrylonitrile-ethylene-propylene-diene-styrene copolymer, an acrylate-styrene-acrylonitrile copolymer, It may contain one or more other thermoplastic resins selected from the group consisting of acrylonitrile-styrene copolymers, polyarylate resins, polystyrene resins, and polyamide resins.

The plasticizer (B2) is preferably an acrylic plasticizer. The glass transition temperature (Tg) of the carrier resin (B1) is preferably -30°C or higher and 150°C or lower.

The thermally expandable microcapsules (A) have a core-shell structure and are composed of a core composed of one or more compounds having a boiling point of 10° C. or higher and 330° C. or lower, and a shell enclosing the core. , the shell comprises a nitrile-based monomer, a (meth)acrylate-based monomer, an aromatic vinyl-based monomer, a diene-based monomer, a vinyl-based monomer having a carboxyl group, a methylol group, a hydroxyl group, It has structural units derived from one or more monomers selected from the group consisting of monomers having one or more reactive functional groups selected from the group consisting of amino groups, epoxy groups, and isocyanate groups. It may be made of resin.

The thermally expandable microcapsules (A) preferably have a maximum expansion temperature of 180°C or higher and 300°C or lower.

In the resin constituting the shell, the concentration of structural units derived from one or more monomers selected from the group consisting of a monomer containing a carboxyl group and a monomer containing an amino group is 12 mmol/g. The following are preferable.

It is preferable that the thermally expandable microcapsules (A) have an average particle size of 0.5 μm or more and 50 μm or less.

The carrier resin (B1) comprises acrylic resin particles (a) having an average particle size of 50 μm to 500 μm and an average particle size covering the acrylic resin particles (a) of 0.05 μm to 0.5 μm. is preferably an acrylic resin containing the acrylic resin particles (b).

The acrylic resin particles (a) are preferably composed of 30 to 100% by weight of (meth)acrylic acid ester and 0 to 70% by weight of a vinyl monomer copolymerizable therewith.

The acrylic resin particles (b) are preferably composed of 30 to 100% by weight of (meth)acrylic acid ester and 0 to 70% by weight of a vinyl monomer copolymerizable therewith.

The acrylic resin particles (b) contain 50 to 100% by weight of a (meth)acrylic acid ester, 0 to 40% by weight of an aromatic vinyl monomer, 0 to 10% by weight of a vinyl monomer copolymerizable therewith, and polyfunctional 50 to 90 parts by weight of latex particles (b1) containing 0 to 5% by weight of monomer, 10 to 100% by weight of (meth)acrylic acid ester, 0 to 90% by weight of aromatic vinyl monomer, and 0 to 25% by weight of vinyl cyanide monomer % and 10 to 50 parts by weight of a monomer mixture (b2) containing 0 to 20% by weight of a vinyl monomer copolymerizable therewith, the latex particles (b1) and the monomer mixture. The total of (b2) is preferably 100 parts by weight.

The masterbatch (C) contains 30% by weight or more and 80% by weight or less of the thermally expandable microcapsules (A), 15% by weight or more and 65% by weight or less of the carrier resin (B1), and the plasticizer (B2). 5% by weight or more and 30% by weight or less, and the content of the carrier resin (B1) is preferably larger than the content of the plasticizer (B2).

The present invention also comprises 1 to 15% by weight of the masterbatch, 30 to 99% by weight of polycarbonate resin, polyester resin, polyester-polyether copolymer, acrylonitrile-butadiene-styrene copolymer, acrylonitrile - One or more selected from the group consisting of ethylene-propylene-diene-styrene copolymers, acrylate-styrene-acrylonitrile copolymers, acrylonitrile-styrene copolymers, polyarylate resins, polystyrene resins, and polyamide resins It relates to a polycarbonate resin composition containing 0 to 55% by weight of another thermoplastic resin.

The polycarbonate-based resin composition may further contain an inorganic compound.

The present invention also relates to an injection foam molded article obtained by injection foam molding the polycarbonate resin composition.

The present invention also relates to a method for producing an injection foam-molded article, which comprises supplying the above-described polycarbonate-based resin composition to an injection molding machine, filling the composition to the initial filling thickness, and then backing the core of the mold.

According to the present invention, there is provided a masterbatch of thermally expandable microcapsules and a polycarbonate-based resin composition, which are capable of obtaining an injection foam molded article of a polycarbonate-based resin composition that suppresses occurrence of whitening and has a good appearance. be able to. Further, according to the present invention, it is possible to obtain an injection foam molded article of a polycarbonate-based resin composition that suppresses the occurrence of whitening and has a good appearance.

FIG. 1 is an explanatory diagram of a mold cavity used when producing an injection foam molded article.

Embodiments of the present invention are described below. It should be noted that the present invention is not limited to the embodiments described below.

<Thermal expandable microcapsules (A)>
First, the thermally expandable microcapsules (A) used in the present invention will be described in detail. The thermally expandable microcapsule (A) is a capsule foaming agent in which a liquid low boiling point compound is wrapped in a thermoplastic polymer shell. The expanded capsule acts as a foaming agent. As the thermally expandable microcapsules (A), for example, those described in JP-A-2011-16884 may be preferably used. Specifically, the thermally expandable microcapsule (A) has a core-shell structure, the core is composed of one or more compounds having a boiling point of 10 ° C. or higher and 330 ° C. or lower, and the shell encloses the core. , is made of thermoplastic resin.

The core may be composed of one or more compounds selected from compounds having a boiling point of 10° C. or higher and 330° C. or higher. Compounds constituting the core are not particularly limited, but examples thereof include hydrocarbons, alcohols, ketones and the like. Examples of hydrocarbons include, but are not limited to, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, eicosane, and these Examples include structural isomers of hydrocarbons. The compound constituting the core is preferably one or more hydrocarbons having a boiling point of 10° C. or higher and 330° C. or lower, more preferably one or more hydrocarbons having a boiling point of 30° C. or higher and 280° C. or lower, and further Preferably, it is one or more hydrocarbons having a boiling point of 30°C or higher and 200°C or lower. By using a compound having a boiling point of 10°C or higher, it is easy to form a masterbatch of the thermally expandable microcapsules (A). Moreover, by using a compound having a boiling point of 330° C. or less, the dispersibility becomes good during polymerization, and the thermally expandable microcapsules can be easily produced.

Examples of the monomer component of the thermoplastic resin constituting the shell of the thermally expandable microcapsule (A) include nitrile-based monomers, (meth)acrylate-based monomers, aromatic vinyl-based monomers, dienes monomer, a vinyl monomer having a carboxyl group, and a monomer having one or more reactive functional groups selected from the group consisting of a methylol group, a hydroxyl group, an amino group, an epoxy group, and an isocyanate group. One or more monomers selected from the group consisting of can be used.

Examples of nitrile monomers include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethoxyacrylonitrile, fumaronitrile and the like.

(Meth)acrylate monomers include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, stearyl (meth)acrylate, lauryl (meth)acrylate, phenyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate and the like. In the present invention, "(meth)acrylate" may be methacrylate or acrylate.

Examples of aromatic vinyl monomers include styrene, α-methylstyrene, vinyltoluene, t-butylstyrene, p-nitrostyrene, chloromethylstyrene and the like.

Examples of diene-based monomers include butadiene, isoprene, and chloroprene.

Examples of vinyl monomers having a carboxyl group include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid and cinnamic acid, maleic acid, itaconic acid, fumaric acid, citraconic acid and chloromalein. Unsaturated dicarboxylic acids such as acids and their anhydrides, unsaturated dicarboxylic acids such as monomethyl maleate, monoethyl maleate, monobutyl maleate, monomethyl fumarate, monoethyl fumarate, monomethyl itaconate, monoethyl itaconate, and monobutyl itaconate Monoester etc. are mentioned.

A monomer having one or more reactive functional groups selected from the group consisting of a methylol group, a hydroxyl group, an amino group, an epoxy group, and an isocyanate group (hereinafter simply referred to as "a monomer having a reactive functional group" Also referred to as.), for example, N-methylol (meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, vinyl glycidyl ether, propenyl glycidyl ether, glycidyl (meth)acrylate, glycerin mono(meth)acrylate, 4-hydroxybutyl(meth)acrylate, 2-hydroxy-3-phenoxypropyl(meth)acrylate, p-hydroxystyrene, blocked isocyanate and the like. Examples of blocked isocyanates include isocyanate compounds (diphenylmethane diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, etc.) such as phenol, alcohol, dimethyl malonate, diethyl malonate, ethyl acetoacetate, oxime, dimethylpyrazole, Examples include blocked isocyanates with methyl ethyl ketone oxime, caprolactam, and the like. In the present invention, "(meth)acrylamide" may be methacrylamide or acrylamide.

From the viewpoint of suppressing decomposition of the main chain of a resin component such as a polycarbonate-based resin by the shell of the thermally expandable microcapsule (A), the thermoplastic resin constituting the shell is the above-described nitrile-based monomer, ( It preferably contains one or more selected from the group consisting of meth)acrylate-based monomers, aromatic vinyl-based monomers, and vinyl-based monomers having a carboxyl group. Further, the thermoplastic resin forming the shell may appropriately contain a chain transfer agent and a monomer having a reactive functional group.

The chain transfer agent is not particularly limited as long as it is used in ordinary radical polymerization. Specifically, a mercaptan-based compound can be used. Mercaptan compounds include, for example, n-dodecylmercaptan, n-octylmercaptan, t-dodecylmercaptan, n-octadecylmercaptan and other alkylmercaptans, 2-mercaptobenzothiazole, bromtrichloromethane, α-methylstyrene dimer, thioglycol. Acid 2-ethylhexyl and the like can be preferably used.

From the viewpoint of preventing the decomposition of resin components such as polycarbonate-based resins and improving the surface properties of the injection foam molded product, the thermoplastic resin constituting the shell contains a monomer containing a carboxyl group and an amino group. The concentration of structural units derived from one or more monomers selected from the group consisting of monomers is preferably 12 mmol/g or less, more preferably 10 mmol/g or less, and further 8 mmol/g or less. Preferably, 5 mmol/g or less is even more preferable, 3 mmol/g or less is even more preferable, and 1 mmol/g or less is particularly preferable. Most preferably not included in The lower limit of the concentration of carboxyl groups in the thermoplastic resin forming the shell may be 0.001 mmol/g or more.

From the viewpoint of suppressing decomposition of the main chain of a resin such as a polycarbonate-based resin, in the thermally expandable microcapsules (A), the concentration of the alkaline substance is preferably 2000 ppm or less, more preferably 1000 ppm or less, and still more preferably 800 ppm. It is below. If it exceeds 2000 ppm, the molecular weight of the polycarbonate-based resin may decrease, and the strength of the molded article may decrease. Examples of the alkaline substance include ion components derived from hydroxides (salts) of alkali metals and/or alkaline earth metals. Specifically, metals such as Li, Na, Mg, K, Ca, and Ba ionic components derived from hydroxides (salts) of

The pH of the thermally expandable microcapsules (A) is desirably near neutral. Thermally expandable microcapsules (A) are generally produced by proceeding suspension polymerization in a mixture containing a polymerizable monomer and a low boiling point compound forming a core in an aqueous dispersion medium. It can be produced by enclosing a low boiling point compound as a core component in a thermoplastic resin shell composed of a polymer. The pH of the heat-expandable microcapsules (A) is desirably adjusted during such polymerization, and generally includes a method of adding a potassium hydrogen phosphate buffer. A preferable range of pH is 6.0 or more and 8.0 or less, a more preferable range is 6.0 or more and 7.5 or less, and a further preferable range is 6.0 or more and 7.0 or less. A method for measuring pH includes a glass electrode method. In the glass electrode method, two electrodes, a glass electrode and a reference electrode, are used, and the potential difference generated between the electrodes is detected and converted into a pH value.

From the viewpoint of not causing a decrease in the molecular weight of the polycarbonate-based resin, the thermoplastic resin constituting the shell in the thermally expandable microcapsules (A) preferably satisfies the following conditions. TG/DTA measurement of pellets obtained by kneading 95 parts by weight of polycarbonate resin and 5 parts by weight of thermoplastic resin constituting the shell with a single screw extruder of φ30 mm at 300 ° C. The temperature at which the weight decreases by 5%. is preferably 200° C. or higher, more preferably 220° C. or higher, still more preferably 240° C. or higher, and most preferably 260° C. or higher. In addition, the weight average molecular weight Mw and number average molecular weight Mn of the pellets are preferably 60% or more, and more preferably 80% or more, with respect to the Mw and Mn of the polycarbonate resin. A more preferred range is 90% or higher, and the most preferred range is 95% or higher.

The thermally expandable microcapsules (A) preferably have an average particle size (unexpanded) of 0.5 µm or more and 50 µm or less, more preferably 0.7 µm or more and 50 µm or less, and still more preferably 1.0 µm. 45 μm or less, more preferably 1.0 μm or more and 40 μm or less, and particularly preferably 1.0 μm or more and 35 μm or less. The maximum particle size of the thermally expandable microcapsules (A) when heated is in the range of about 3 to 5 times the average particle size of the unexpanded microcapsules. If the average particle size when unexpanded is 0.5 μm or more and 50 μm or less, the particle size when expanded is about 1.5 μm or more and 250 μm or less, and the decrease in Charpy impact strength and surface impact strength during foaming is greatly reduced. can be suppressed. The average particle size of the unexpanded thermally expandable microcapsules (A) can be measured with a particle size distribution analyzer, specifically a particle size distribution analyzer SALD-3000J manufactured by Shimadzu Corporation.

The thermally expandable microcapsules (A) have a maximum expansion temperature (also referred to as maximum foaming temperature) of preferably 180° C. or higher and 300° C. or lower, more preferably 190° C. or higher and 290° C. or lower, still more preferably 200° C. °C or higher and 280 °C or lower, and particularly preferably 210 °C or higher and 270 °C or lower. In the present invention, the maximum expansion temperature of the thermally expandable microcapsules (A) can be measured by the measuring method described in Japanese Patent No. 5484673. Specifically, "TMA measurement" is performed using TMA-7 manufactured by Birkin Elmer. About 0.25 mg of the sample is placed in a container, the temperature is raised at a temperature increase rate of 5 ° C./min, and the height displacement is continuously measured. is the maximum expansion temperature. When the maximum expansion temperature of the thermally expandable microcapsules (A) is within the above range, it matches the molding temperature of the polycarbonate-based resin, so that an injection foam molded article with low density and high strength can be easily obtained.

<Carrier Resin Composition (B)>
The carrier resin composition (B) is substantially compatible with the polycarbonate resin, and has a shear viscosity at 80° C. of 1.0 Pa·s or more and 1.5×10 ⁶ Pa·s or less. As a result, in the foamed resin molding of the polycarbonate resin composition using the masterbatch of the thermally expandable microcapsules (A) masterbatched with the carrier resin composition (B), whitening is suppressed and the appearance is improved. Become. In the present invention, "substantially compatible with the polycarbonate resin" specifically means that a mixture of the carrier resin composition (B) and the polycarbonate resin is measured by differential scanning calorimetry (DSC) at a glass transition temperature of It means that the peak of becomes one.

The shear viscosity of the carrier resin composition (B) at 80° C. is 1.0 Pa·s or more and 1.5×10 ⁶ Pa·s or less, so that the thermally expandable microcapsules (A) are in the carrier resin composition (B ) to obtain a uniformly dispersed masterbatch. Specifically, when the thermally expandable microcapsules (A) and the carrier resin composition (B) are kneaded at 130°C to prepare a masterbatch, the viscosity of the carrier resin composition (B) is low. , the heat-expandable microcapsules (A) are not subjected to shear and can be pelletized without expanding the heat-expandable microcapsules (A). From the viewpoint of improving workability in masterbatching, the carrier resin composition (B) preferably has a shear viscosity at 80° C. of 1.0 Pa·s or more and 1.0×10 ⁶ Pa·s or less. s or more and 6×10 ⁵ Pa·s or less, more preferably 1.0 Pa·s or more and 3×10 ⁵ Pa·s or less, still more preferably 5 Pa·s or more and 1.5×10 ⁵ Pa·s or less, It is more preferably 1.0×10 ² Pa.s or more and 1.5×10 ⁵ Pa.s or less, and particularly preferably 1.0×10 ³ Pa.s or more and 1.5×10 ⁵ Pa.s or less. The shear viscosity at 80° C. of the carrier resin composition (B) can be measured using a Shimadzu flow tester (model CFT-500C). Specifically, the measurement start temperature is set to 50° C., the carrier resin composition (B) is allowed to flow in a capillary having a diameter of 1.0 mm and a length of 10 mm under a constant load of 30 kgf, and the temperature is raised at a rate of 10° C./min. , the shear viscosity is measured when the measurement temperature reaches 80°C.

<Carrier resin (B1)>
The carrier resin (B1) may be an acrylic resin having a weight average molecular weight of 8,000 or more and 350,000 or less. Preferably, the weight average molecular weight of the carrier resin (B1) is 10,000 or more and 330,000 or less, more preferably 10,000 or more and 300,000 or less, and still more preferably 10,000 or more and 280,000 or less. more preferably 14,000 or more and 330,000 or less, still more preferably 14,000 or more and 300,000 or less, still more preferably 14,000 or more and 280,000 or less, still more preferably is 14,000 or more and 200,000 or less, and particularly preferably 14,000 or more and 100,000 or less. Alternatively, the weight average molecular weight of the carrier resin (B1) is preferably 16,000 or more and 330,000 or less, more preferably 16,000 or more and 300,000 or less, and even more preferably 16,000 or more and 280,000 or less. 000 or less, more preferably 16,000 or more and 200,000 or less, and particularly preferably 16,000 or more and 100,000 or less. Alternatively, the weight average molecular weight of the carrier resin (B1) is preferably 19,000 or more and 330,000 or less, more preferably 19,000 or more and 300,000 or less, even more preferably 19,000 or more and 280,000 or less. 000 or less, more preferably 19,000 or more and 200,000 or less, and particularly preferably 19,000 or more and 100,000 or less. In the present invention, the weight average molecular weight and number average molecular weight of the resin are measured by GPC (gel permeation chromatography).

Carrier resin (B1) is solid at 20°C. The handleability is excellent, and the workability of the masterbatch (C) is improved. The carrier resin (B1) is preferably solid at room temperature (more than 20° C. and 25° C. or less) from the viewpoint of handleability.

The carrier resin (B1) preferably has a glass transition temperature of −30° C. or higher and 150° C. or lower, more preferably −10° C. or higher and 140° C. or lower, from the viewpoint of workability of the masterbatch (C). More preferably, the temperature is 10°C or higher and 130°C or lower.

The carrier resin (B1) is not particularly limited, but from the viewpoint of compatibility with the polycarbonate resin, for example, acrylic resin particles (a) having an average particle size of 50 μm or more and 500 μm or less and acrylic resin particles (a) It is more preferable that the acrylic resin contains acrylic resin particles (b) having an average particle size of 0.05 μm or more and 0.5 μm or less that coat the .

The acrylic resin particles (a) may have an average particle size of 50 μm to 500 μm, preferably 75 μm to 300 μm, more preferably 100 μm to 250 μm. The acrylic resin particles (a) having the above average particle size can be obtained by a suspension polymerization method. When the average particle size of the acrylic resin particles (a) is 50 μm or more, the filterability is improved. Can be mixed. The average particle size of the acrylic resin particles (a) is measured using Microtrac MT3300 manufactured by Microtrac Bell Co., Ltd.

In the carrier resin (B1), the acrylic resin particles (b) covering the acrylic resin particles (a) means that the entire surface of the acrylic resin particles (a) is covered with the acrylic resin particles (b). Alternatively, the surface of the acrylic resin particles (a) may be partially covered with the acrylic resin particles (b). It is preferable that 50% or more of the surface area of the acrylic resin particles (a) is covered with the acrylic resin particles (b), and 60% or more is more preferably covered. When the surface area covered is 50% or more, the carrier resin (B1) has good powder characteristics.

By coating the acrylic resin particles (a) with the acrylic resin particles (b), the average particle size of the acrylic resin particles (a) is preferably increased by 3% or more and 50% or less compared to before coating. When the change in the acrylic resin particles (a) is less than 3%, the acrylic resin particles (a) remain in the system, and as a result, filterability tends to be difficult to improve. That is, the average particle size of the carrier resin (B1) is preferably 3% or more and 50% or less larger than the average particle size of the acrylic resin particles (a). The average particle size of the carrier resin (B1) is measured using Microtrac MT3300 manufactured by Microtrac Bell Co., Ltd.

The acrylic resin particles (a) contain 30 to 100% by weight of a (meth)acrylic acid ester and 0 of a vinyl monomer copolymerizable therewith, from the viewpoint of easily controlling dust accompanying a polymer obtained by suspension polymerization. It is preferably composed of ~70% by weight. More preferably, it comprises 70 to 100% by weight of (meth)acrylic acid ester and 0 to 30% by weight of a vinyl monomer copolymerizable therewith. In the acrylic resin particles (a), when the content of the structural unit derived from the (meth)acrylic acid ester is 30% by weight or more, the compatibility with the acrylic resin particles (b) is good, and the molding process is favorable. Become. In the present invention, "(meth)acrylic acid" may be methacrylic acid or acrylic acid.

The (meth)acrylic acid ester is not particularly limited, but for example, alkyl acrylates having an alkyl group having 10 or less carbon atoms such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and Examples thereof include alkyl methacrylates having an alkyl group having 10 or less carbon atoms such as methyl methacrylate, ethyl methacrylate, butyl methacrylate and 2-ethylhexyl methacrylate. These may be used individually by 1 type, and can be used in combination of 2 or more types. Among these, one selected from the group consisting of methyl methacrylate, butyl methacrylate, ethyl acrylate and butyl acrylate from the viewpoint of obtaining a good-quality molded product in combination with the acrylic resin particles (b). It is preferable that it is above.

In addition, vinyl monomers copolymerizable with (meth)acrylic acid esters are not particularly limited, but examples include aromatic vinyl monomers such as styrene, α-methylstyrene, monochlorostyrene and dichlorostyrene; vinyl carboxylic acid monomers; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; halogenated vinyl monomers such as vinyl chloride, vinyl bromide and chloroprene; alkenes such as vinyl acetate, ethylene, propylene, butylene, butadiene and isobutylene; Halogenated alkenes; polyfunctional monomers such as allyl methacrylate, diallyl phthalate, triallyl cyanurate, monoethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, divinylbenzene, glycidyl methacrylate, etc. etc. These may be used individually by 1 type, and can be used in combination of 2 or more types. Among these, styrene, α-methylstyrene, acrylic acid, methacrylic acid, acrylonitrile, vinyl acetate, allyl methacrylate and methacrylic are preferred from the viewpoint of obtaining a good-quality molded product in combination with the acrylic resin particles (b). One or more selected from the group consisting of glycidyl acid is preferred.

The acrylic resin particles (a) are homopolymer particles or mixed polymer particles obtained by suspension polymerization of one or more of the above-mentioned monomers, and in some cases copolymerization or graft polymerization. can be done.

As the dispersion stabilizer in suspension polymerization, for example, a common inorganic dispersant or organic dispersant can be used. Examples of inorganic dispersants include magnesium carbonate and tribasic calcium phosphate. Examples of organic dispersants include starch, gelatin, acrylamide, partially saponified polyvinyl alcohol (PVA), partially saponified polymethyl methacrylate, polyacrylic acid, salts of polyacrylic acid, cellulose, methyl cellulose, hydroxymethyl cellulose, hydroxy Natural and synthetic polymer dispersants such as ethyl cellulose, polyalkylene oxide, polyvinylpyrrolidone, polyvinylimidazole, and sulfonated polystyrene, and low-molecular-weight dispersants (also called emulsifiers) such as alkylbenzenesulfonates and fatty acid salts. ) and the like.

Polymerization initiators for suspension polymerization include peroxides such as benzoyl peroxide and lauroyl peroxide, and azo compounds such as azobisisobutyronitrile.

A chain transfer agent may also be used for molecular weight control. Chain transfer agents include alkylmercaptans having 2 to 18 carbon atoms; mercapto acids such as thioglycolic acid esters and β-mercaptopropionic acid; aromatic mercaptans such as benzylmercaptan, thiophenol, thiocresol and thionaphthol. . Examples of alkylmercaptans having 2 to 18 carbon atoms include n-dodecylmercaptan, n-octylmercaptan, t-dodecylmercaptan, n-octadecylmercaptan and the like. Among these, alkyl mercaptans having 4 to 12 carbon atoms are preferred. Thioglycolic acid esters include, for example, 2-ethylhexyl thioglycolate.

The amounts of the dispersion stabilizer, polymerization initiator and chain transfer agent to be added can be appropriately set according to the physical properties of the monomers to be used and the desired suspension polymer particles (acrylic resin particles (a)). can.

The method for producing the suspended polymer particles is not particularly limited, and all commonly available methods can be used. For example, a method of suspending a monomer or a monomer mixture in water and conducting a polymerization reaction as it is, a method of suspending a part of a monomer or a monomer mixture in water to initiate a polymerization reaction, and a polymerization reaction Along with the progress of, the remaining monomer or monomer mixture aqueous suspension is divided into one stage or several stages, or continuously added to the polymerization reaction tank to carry out the polymerization reaction. Alternatively, a part of the monomer mixture is suspended in water to initiate the polymerization reaction, and as the polymerization reaction progresses, the remaining monomer or monomer mixture is added in one stage, in several stages, or continuously. and a method of carrying out the polymerization reaction by adding it to the polymerization reaction tank.

The method of adding the polymerization initiator and the chain transfer agent is not particularly limited. The practiced approach is preferred. The time required for polymerization varies depending on the type and amount of the polymerization initiator, the polymerization temperature, etc., but is usually 1 to 24 hours. Further, it is also possible to add additives such as plasticizers, lubricants, stabilizers and ultraviolet absorbers which are usually added during plastic molding during suspension polymerization to the monomers.

The acrylic resin particles (b) may have an average particle size of 0.05 μm or more and 0.5 μm or less, preferably 0.06 μm or more and 0.3 μm or less. The acrylic resin particles (b) having the above average particle size can be obtained by an emulsion polymerization method. When the average particle size of the acrylic resin particles (b) is within the range described above, the workability when molding the carrier resin (B1), and the impact strength and transparency of the resulting molded product are improved. Cheap. The average particle size of the acrylic resin particles (b) is measured using Microtrac MT3300 manufactured by Microtrac Bell Co., Ltd.

The acrylic resin particles (b) preferably comprise 30 to 100% by weight of a (meth)acrylic acid ester and 0 to 70% by weight of a vinyl monomer copolymerizable therewith. Latex particles (b1) 50 composed of 50 to 100% by weight, 0 to 40% by weight of an aromatic vinyl monomer, 0 to 10% by weight of a vinyl monomer copolymerizable therewith, and 0 to 5% by weight of a polyfunctional monomer ~90 parts by weight, 10 to 100% by weight (meth)acrylic acid ester, 0 to 90% by weight of an aromatic vinyl monomer, 0 to 25% by weight of a vinyl cyanide monomer, and 0 to 20% by weight of a vinyl monomer copolymerizable therewith. Polymer particles obtained by polymerizing 10 to 50 parts by weight of the monomer mixture (b2) containing % by weight, and the total of the latex particles (b1) and the monomer mixture (b2) is 100 parts by weight. preferable.

The (meth)acrylic acid ester that constitutes the acrylic resin particles (b) is not particularly limited, and for example, the (meth)acrylic acid esters listed when describing the acrylic resin particles (a) can be used as appropriate. can. In addition, the aromatic vinyl monomer, vinyl cyanide monomer, polyfunctional monomer, and other copolymerizable vinyl monomers constituting the acrylic resin particles (b) are not particularly limited. Those listed in the description of a) can be used as appropriate.

The acrylic resin particles (b) more preferably contain 50 to 95% by weight of methyl methacrylate, 5 to 50% by weight of a methacrylic acid ester having an alkyl group having 2 to 8 carbon atoms, and 0 vinyl monomer copolymerizable therewith. 70 to 95 parts by weight of latex particles (b1) obtained by emulsion polymerization of a monomer mixture (a) containing up to 20% by weight, and one or more selected from the group consisting of acrylic acid esters and methacrylic acid esters other than methyl methacrylate. Graft polymerization of 5 to 30 parts by weight of a monomer mixture (b2) containing 20 to 80% by weight of the monomer, 20 to 80% by weight of methyl methacrylate, and 0 to 20% by weight of a vinyl monomer copolymerizable therewith. The total amount of the latex particles (b1) and the monomer mixture (b2) is 100 parts by weight. Specifically, a monomer containing 50 to 95% by weight of methyl methacrylate, 5 to 50% by weight of a methacrylic acid ester having an alkyl group of 2 to 8 carbon atoms, and 0 to 20% by weight of a vinyl monomer copolymerizable therewith. 70 to 95 parts by weight of the mixture (I) is emulsion polymerized, and in the presence of the obtained polymer latex, one or more monomers selected from the group consisting of acrylic acid esters and methacrylic acid esters excluding methyl methacrylate. by graft polymerizing 5 to 30 parts by weight of a monomer mixture (II) containing 20 to 80% by weight of a polymer, 20 to 80% by weight of methyl methacrylate, and 0 to 20% by weight of a vinyl monomer copolymerizable therewith. The resulting emulsion polymer particles preferably contain 100 parts by weight of the monomer mixture (I) and the monomer mixture (II) in total.

Acrylic resin particles (b) more preferably contain 40 to 99.99% by weight of methyl methacrylate, 0 to 59.99% by weight of a vinyl monomer copolymerizable therewith, and 0.01 to 10% by weight of a polyfunctional monomer. 10 to 60 parts by weight of the polymerized first-stage polymer (III), 60 to 99.9% by weight of alkyl acrylate, and 0 to 39.9% by weight of a vinyl monomer copolymerizable therewith. And obtained by polymerizing 40 to 90 parts by weight of a monomer mixture (IV) containing 0.1 to 5% by weight of a polyfunctional monomer, the total of the monomer mixture (III) and the monomer mixture (IV) 100 parts by weight of second-stage polymer particles (latex particles (b1)) in which is 100 parts by weight, 60 to 100% by weight of (meth)acrylic acid ester, and 0 to 40% by weight of a vinyl monomer copolymerizable therewith. Emulsion polymer particles obtained by polymerizing 11 to 67 parts by weight of a monomer mixture containing Specifically, a monomer mixture containing 40 to 99.99% by weight of methyl methacrylate, 0 to 59.99% by weight of a vinyl monomer copolymerizable therewith and 0.01 to 10% by weight of a polyfunctional monomer ( III) 60 to 99.9% by weight of alkyl acrylate and 0 to 39.9% by weight of a vinyl monomer copolymerizable therewith in the presence of the first-stage polymer latex obtained by emulsion polymerization of 10 to 60 parts by weight. 40 to 90 parts by weight of a monomer mixture (IV) containing 9% by weight and 0.1 to 5% by weight of a polyfunctional monomer is emulsion polymerized to obtain a second-stage polymer latex, and a monomer mixture (III) and a total of 100 parts by weight of the monomer mixture (IV), and in the presence of 100 parts by weight of the solid content (latex particles (b1)) of the obtained second-stage polymer latex, (meth)acrylic acid Emulsion polymer particles having a three-layer structure obtained by polymerizing 11 to 67 parts by weight of a monomer mixture (b2) containing 60 to 100% by weight of an ester and 0 to 40% by weight of a vinyl monomer copolymerizable therewith. .

The latex particles (b1) preferably have a glass transition temperature of 0° C. or lower, more preferably −30° C. or lower. When the glass transition temperature of the latex particles (b1) is 0° C. or lower, the impact resistance strength of the injection foam molded article is likely to be improved.

The carrier resin (B1) preferably contains 22 parts by weight or more and 100 parts by weight or less of the acrylic resin particles (b) with respect to 100 parts by weight of the acrylic resin particles (a), and more preferably 25 parts by weight or more and 100 parts by weight or less. It is more preferable to contain 30 parts by weight or more and 100 parts by weight or less. If the acrylic resin particles (b) are less than 22 parts by weight per 100 parts by weight of the acrylic resin particles (a), the filterability may not be improved. Further, when the amount of the acrylic resin particles (b) exceeds 100 parts by weight relative to 100 parts by weight of the acrylic resin particles (a), the moisture content of the carrier resin (B1) after dehydration may increase.

Although the carrier resin (B1) is not particularly limited, it can be produced, for example, as follows. First, a suspension containing acrylic resin particles (a) is prepared by suspension polymerization, and an emulsion polymerized latex containing acrylic polymer particles (b) is prepared by emulsion polymerization. Next, the suspension and the emulsion polymerization latex are mixed. Next, the solid content concentration (total concentration of acrylic polymer particles (a) and acrylic polymer particles (b)) in the resulting mixed suspension is adjusted to 25% by weight or more and 35% by weight or less. Next, to the mixed suspension having the adjusted solid content concentration, an aqueous electrolyte solution is added at a temperature equal to or lower than the Vicat softening temperature of the acrylic polymer particles (b). After heating to a high temperature, the carrier resin (B1) is recovered by solid-liquid separation. By the above-described production method, the surface of the acrylic polymer particles (a) can be uniformly coated with the acrylic polymer particles (b), and the acrylic polymer particles (b) that cause deterioration in filterability It is possible to significantly reduce the remaining

The method of mixing the suspension containing the acrylic resin particles (a) obtained by suspension polymerization and the emulsion polymerized latex containing the acrylic polymer particles (b) obtained by emulsion polymerization comprises, under stirring, It is preferable to add the emulsion-polymerized latex to the suspension or to add the suspension to the emulsion-polymerized latex while stirring.

The solid content ratio of the suspension containing the acrylic resin particles (a) and the emulsion polymerization latex containing the acrylic polymer particles (b) is that the acrylic resin particles (a) are 100 parts by weight per 100 parts by weight of the acrylic polymer. The content of particles (b) is preferably 22 to 100 parts by weight, more preferably 25 to 100 parts by weight, and even more preferably 30 to 100 parts by weight. If the amount of the acrylic polymer particles (b) is 22 parts by weight or more relative to 100 parts by weight of the acrylic resin particles (a), the amount of the acrylic resin particles (b) remaining in the system is reduced, resulting in filtration. Easy to improve. Further, if the amount of the acrylic polymer particles (b) is 100 parts by weight or less relative to 100 parts by weight of the acrylic resin particles (a), the resulting carrier resin (B1) will have a low moisture content after dehydration.

When mixing the suspension and the emulsion-polymerized latex, the solid content concentration of the suspension and the emulsion-polymerized latex is not particularly limited. It is preferable to use it as it is because it is the simplest in terms of production. Generally, the solid content concentration of the suspension containing acrylic resin particles (a) (concentration of acrylic resin particles (a)) is preferably 25% by weight or more and 55% by weight or less, and preferably 30% by weight or more and 45% by weight. It is more preferably 33 wt % or more and 45 wt % or less, and particularly preferably 35 wt % or more and 40 wt % or less. The solid content concentration of the emulsion polymerized latex containing acrylic resin particles (b) (concentration of acrylic resin particles (b)) is preferably 25% by weight or more and 55% by weight or less, and 25% by weight or more and 45% by weight or less. is more preferably 30% by weight or more and 45% by weight or less, and particularly preferably 30% by weight or more and 40% by weight or less. The temperature at the time of mixing is preferably 5° C. or higher, and if it is lower than 5° C., there is a tendency that it is not preferable because the amount of utility usage for the subsequent heat treatment operation becomes large.

The solid content concentration (concentration of polymer particles) in the mixed suspension when the aqueous electrolyte solution is added is preferably 25% by weight or more and 35% by weight or less, and is 27% by weight or more and 33% by weight or less. is more preferable. If the concentration of the polymer particles (solid content) in the mixed suspension when the aqueous electrolyte solution is added is 25% by weight or more, the particles in the mixed suspension after the addition of the aqueous electrolyte solution and heat treatment are The formation of fine aggregates having a diameter of 50 μm or less is suppressed, the filterability is improved, and the post-dehydration water content of the carrier resin (B1) is lowered. Further, when the concentration of the polymer particles in the mixed suspension when the aqueous electrolyte solution is added is 35% by weight or less, the formation of secondary aggregated particles via the acrylic resin particles (b) is suppressed, and the carrier The moisture content of the resin (B1) after dehydration is lowered.

The electrolyte aqueous solution is preferably added to the mixed suspension under stirring. By this operation, the acrylic resin particles (b), which are emulsion polymer particles, coagulate (precipitate) on the surface of the acrylic resin particles (a), which are suspension polymer particles, and the surface of the acrylic resin particles (a) to cover. The addition of the aqueous electrolyte solution should be carried out after mixing the suspension polymerized suspension and the emulsion polymerized latex. The reason for this is that if an aqueous electrolyte solution is present when the suspension for suspension polymerization and the emulsion polymerization latex are mixed, the shape of the carrier resin (B1) produced is distorted and the water content after dehydration increases, and the water content increases. The solidified acrylic resin particles (b) tend to remain and the filterability tends to be extremely deteriorated. For example, if the emulsion polymerization latex is added after adding the aqueous electrolyte solution to the suspension polymerization suspension, the uniformity of the coating of the acrylic resin particles (b) on the surface of the acrylic resin particles (a) decreases, and A problem arises in that the residual amount of the acrylic polymer particles (b), which causes deterioration of filterability, increases significantly.

As the electrolyte aqueous solution, an aqueous solution of an organic acid, an organic acid salt, an inorganic acid, or an inorganic salt having properties capable of coagulating and solidifying the acrylic resin particles (b) can be appropriately used. Examples of the aqueous electrolyte solution include sodium chloride, potassium chloride, lithium chloride, sodium bromide, potassium bromide, lithium bromide, potassium iodide, sodium iodide, potassium sulfate, sodium sulfate, ammonium sulfate, ammonium chloride, and sodium nitrate. , potassium nitrate, calcium chloride, ferrous sulfate, magnesium sulfate, zinc sulfate, copper sulfate, barium chloride, ferrous chloride, ferric chloride, magnesium chloride, ferric sulfate, aluminum sulfate, potassium alum, iron alum, etc. Aqueous solutions of inorganic salts, aqueous solutions of inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid, organic acids such as acetic acid and formic acid and their aqueous solutions, organic acid salts such as sodium acetate, calcium acetate, sodium formate and calcium formate An aqueous solution and the like are included. These may be used individually by 1 type, and can be used in mixture of 2 or more types. Among them, the uniformity of the coating of the surface of the acrylic resin particles (a) with the acrylic resin particles (b), the significant reduction of the remaining acrylic polymer particles (b) that cause deterioration of filterability, and the improvement of wastewater treatment. In terms of ease, aqueous solutions of inorganic salts such as sodium chloride, potassium chloride, sodium sulfate, ammonium chloride, calcium chloride, magnesium chloride, magnesium sulfate, barium chloride, ferrous chloride, aluminum sulfate, potassium alum, iron alum, etc. Aqueous solutions of inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid can be preferably used.

The concentration of the aqueous electrolyte solution is preferably 0.001% by weight or more, more preferably 0.1% by weight or more, and even more preferably 1% by weight or more. If the concentration of the electrolyte aqueous solution is less than 0.001% by weight, it is necessary to add a large amount of the electrolyte aqueous solution in order to coagulate the acrylic resin particles (b), resulting in a large amount of utility usage during the subsequent heat treatment operation. There is a possibility that it will be.

The addition of the aqueous electrolyte solution must be carried out at a temperature not higher than the Vicat softening temperature of the acrylic resin particles (b). If the temperature of the mixed suspension exceeds the Vicat softening temperature of the acrylic resin particles (b) when the aqueous electrolyte solution is added, the shape of the resulting carrier resin (B1) may be distorted and the moisture content after dehydration may increase. There is a tendency that uncoagulated acrylic resin particles (b) remain to cause extreme deterioration of filterability, and aggregation between carrier resins (B1) frequently occurs.

If the ratio of emulsion polymerized latex in the mixed suspension is high, or if the rate of addition of the aqueous electrolyte solution is extremely high, or if the concentration of the aqueous electrolyte solution is extremely high, the viscosity increases significantly when the aqueous electrolyte solution is added. There is In such a case, the viscosity of the system may be reduced to such an extent that normal stirring conditions can be maintained, such as adding water as appropriate to the system. The amount of the aqueous electrolyte solution naturally varies depending on the ratio of the acrylic resin particles (b) in the mixed suspension, but it is sufficient to add an amount at which unsolidified acrylic resin particles (b) are no longer present after the heat treatment.

After adding the aqueous electrolyte solution to the mixed suspension, if the aqueous electrolyte solution is an acidic aqueous solution and the mixed suspension after granulation is acidic, neutralize with an alkali such as sodium hydroxide, or the aqueous electrolyte solution is neutralized. In the case of an aqueous solution with a high viscosity, it is preferable to heat-treat it as it is at a temperature higher than the Vicat softening temperature of the acrylic polymer particles (b), for example, 50 to 120°C. The heat treatment densifies the aggregates of the acrylic polymer particles (b) covering the surfaces of the acrylic polymer particles (a), thereby reducing the moisture content of the obtained carrier resin (B1). Thereafter, dehydration and drying are carried out according to a conventional method to obtain the carrier resin (B1).

<Plasticizer (B2)>
The plasticizer (B2) may have a weight average molecular weight of 1,000 or more and 20,000 or less. Thereby, a carrier resin composition (B) having a shear viscosity at 80° C. of 1.0 Pa·s or more and 1.5×10 ⁶ Pa·s or less can be obtained. The weight average molecular weight of the plasticizer (B2) is preferably 1,000 or more and 18,000 or less, more preferably 1,000 or more and 15,000 or less, and 1,000 or more and 13,000 or less. is more preferred. From the viewpoint of compatibility with the polycarbonate-based resin, the plasticizer (B2) is preferably an acrylic plasticizer, a polyester plasticizer, or the like, and more preferably an acrylic plasticizer.

The plasticizer (B2) has a viscosity at 25°C of preferably 300 mPa s or more and 100,000 mPa s or less, more preferably 350 mPa s or more and 90,000 mPa s or less, and 400 mPa s or more and 80 mPa s or more. ,000 mPa·s or less. When the viscosity of the plasticizer (B2) at 25°C is within the above range, the carrier resin composition (B) having a shear viscosity at 80°C of 1.0 Pa·s or more and 1.5×10 ⁶ Pa·s or less can be obtained. easier. The plasticizer (B2) is liquid at 20°C. The workability of the masterbatch (C) is improved. The plasticizer (B2) is preferably liquid at room temperature (more than 20° C. and 25° C. or less). The viscosity of the plasticizer (B2) at 25° C. can be measured using an E-type viscometer according to JIS Z 8803-1991.

As the plasticizer (B2), those generally known as acrylic plasticizers can be used, and non-functional acrylic plasticizers are preferably used. Examples of acrylic plasticizers include (meth)acrylic acid ester polymers, (meth)acrylic acid ester-aromatic vinyl monomer copolymers, and the like, and (meth)acrylic acid ester polymers are preferred. The (meth)acrylic acid ester polymer includes a homopolymer of alkyl acrylate, a homopolymer of alkyl methacrylate, a copolymer of alkyl acrylates, a copolymer of alkyl methacrylates, an acrylic Including copolymers of acid alkyl esters and methacrylic acid alkyl esters. The (meth)acrylic acid ester that constitutes the acrylic plasticizer is not particularly limited, and for example, the (meth)acrylic acid esters listed in the explanation of the acrylic resin particles (a) can be used as appropriate. In addition, the aromatic vinyl monomer constituting the acrylic plasticizer is not particularly limited, and for example, those listed in the explanation of the acrylic resin particles (a) can be appropriately used.

The plasticizer (B2) is not particularly limited, but specifically, product names manufactured by Toagosei Co., Ltd. "UP-1000", "UP-1010", "UP-1020", "UP-1021", " Commercially available non-functional type acrylic plasticizers such as Alfon UP-1000 series such as "UP-1061" and "UP-1500" can be used.

<Masterbatch (C)>
The masterbatch (C) contains thermally expandable microcapsules (A) and a carrier resin composition (B), and the carrier resin composition (B) contains a carrier resin (B1) and a plasticizer (B2). In the masterbatch (C), the carrier resin composition (B) mixed with the thermally expandable microcapsules (A) has a shear viscosity at 80° C. of 1.0 Pa·s or more and 1.5×10 ⁶ Pa·s or less. As a result, a masterbatch in which the thermally expandable microcapsules (A) are uniformly dispersed can be obtained using the carrier resin composition (B) without impairing foaming power. In addition, since the carrier resin composition (B) is substantially compatible with the polycarbonate resin, when the masterbatch (C) is used, whitening is suppressed, and an injection foam molded article with a good appearance can be obtained. can. That is, in injection foam molding using the masterbatch (C) of the thermally expandable microcapsules (A) obtained above, a molded article with good appearance can be obtained without impairing the foaming power.

In the masterbatch (C), the concentration of the thermally expandable microcapsules (A) is preferably 30% by weight or more and 80% by weight or less, and more preferably, from the viewpoint of handleability, storage stability, dispersibility in the base resin, etc. is 30% by weight or more and 70% by weight or less, more preferably 30% by weight or more and 60% by weight or less.

The masterbatch (C) preferably contains 20% by weight or more and 70% by weight or less of the carrier resin composition (B), more preferably 30% by weight or more and 70% by weight, from the viewpoint of compatibility with the polycarbonate resin and workability. % by weight or less, more preferably 40% by weight or more and 70% by weight or less.

From the viewpoint of compatibility with the polycarbonate resin and shear viscosity at 80 ° C., the masterbatch (C) specifically contains 30% by weight or more and 80% by weight or less of the thermally expandable microcapsules (A), and a carrier resin ( 15% by weight or more and 65% by weight or less of B1) and 5% by weight or more and 30% by weight or less of the plasticizer (B2), and the content of the carrier resin (B1) is higher than the content of the plasticizer (B2). preferable. The masterbatch (C) contains 30% by weight or more and 80% by weight or less of the thermally expandable microcapsules (A), 15% by weight or more and 40% by weight or less of the carrier resin (B1), and 5% by weight or more of the plasticizer (B2). It is more preferable to contain 30% by weight or less. More preferably, the masterbatch (C) contains 30% by weight or more and 80% by weight or less of the thermally expandable microcapsules (A), 12% by weight or more and 50% by weight or less of the carrier resin (B1), and a plasticizer (B2). 8% by weight or more and 25% by weight or less. Particularly preferably, the masterbatch (C) contains 30% by weight or more and 80% by weight or less of the thermally expandable microcapsules (C), 12% by weight or more and 45% by weight or less of the carrier resin (B1), and the plasticizer (B2). 8% by weight or more and 20% by weight or less.

The masterbatch (C) can be suitably used for polycarbonate resins. The polycarbonate-based resin may be a polycarbonate-based resin (G) itself described later, and a polycarbonate-based resin (G), a polyester-based resin, a polyester-polyether copolymer, an acrylonitrile-butadiene-styrene copolymer, One selected from the group consisting of acrylonitrile-ethylene-propylene-diene-styrene copolymer, acrylate-styrene-acrylonitrile copolymer, acrylonitrile-styrene copolymer, polyarylate resin, polystyrene resin, and polyamide resin Mixed resins of other thermoplastic resins described above may also be used. When the polycarbonate-based resin is a mixed resin, the content of the polycarbonate-based resin (G) is the largest among all the resins contained in the mixed resin. When the polycarbonate-based resin is a mixed resin, the masterbatch (C) preferably has compatibility with the mixed resin.

<Polycarbonate resin composition>
A polycarbonate-based resin composition is a resin composition containing a polycarbonate-based resin (G) and a masterbatch (C) and having a polycarbonate-based resin as a main component. Here, the "main component" means that the content of the polycarbonate-based resin is the largest among all components contained in the polycarbonate-based resin composition. In the polycarbonate-based resin composition, components other than the masterbatch (C) are also referred to as base components.

In the polycarbonate-based resin composition, the content of the masterbatch (C) may be appropriately set according to the expansion ratio of the final product, the type of foaming agent, the resin temperature during molding, and the like. The content of the masterbatch (C) in the polycarbonate resin composition is preferably 1% by weight or more and 20% by weight or less, more preferably 2% by weight or more and 15% by weight or less, and particularly 3% by weight or more and 10% by weight or less. preferable. By using the masterbatch (C) in this range, it is easy to economically obtain a foamed article having an expansion ratio of 1.1 times or more and uniform fine cells.

<Polycarbonate resin (G)>
Polycarbonate-based resin (G) is a polycarbonate-based resin derived from a compound having two phenolic hydroxyl groups (hereinafter referred to as dihydric phenol), and is usually dihydric phenol and phosgene, or dihydric phenol and carbonic acid diester. It is a resin obtained by the reaction with

Examples of the dihydric phenol include biphenol, methylenebisphenol (bisphenol F), bis(4-hydroxyphenyl)sulfone (bisphenol S), 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) and the like. Among these, bisphenol A is preferable, but it is not limited to this.

The polycarbonate resin (G) preferably has a number average molecular weight of 10,000 or more and 60,000 or less, preferably 10,000 or more and 30,000 or less, from the viewpoint of impact resistance, chemical resistance, moldability, etc. is more preferred. The content of the polycarbonate resin (G) in the polycarbonate resin composition is preferably 30% by weight or more and 99% by weight or less, more preferably 30% by weight or more and 80% by weight or less, and still more preferably 30% by weight or more and 70% by weight. % or less.

The polycarbonate-based resin composition further includes a polyester-based resin, a polyester-polyether copolymer, an acrylonitrile-butadiene-styrene copolymer, an acrylonitrile-ethylene-propylene-diene-styrene copolymer, an acrylate-styrene-acrylonitrile copolymer. It may also contain one or more other thermoplastic resins selected from the group consisting of coalesced, acrylonitrile-styrene copolymers, polyarylate resins, polystyrene-based resins, and polyamide-based resins.

<Polyester resin (H1)>
The polyester-based resin (H1) includes amorphous thermoplastic polyester-based resins such as amorphous aliphatic polyester, amorphous semi-aromatic polyester, amorphous wholly aromatic polyester, crystalline aliphatic polyester, crystalline semi-aromatic polyester, etc. Aromatic polyester, crystalline thermoplastic polyester resin such as crystalline wholly aromatic polyester, liquid crystalline thermoplastic polyester resin such as liquid crystalline aliphatic polyester, liquid crystalline semi-aromatic polyester, liquid crystalline wholly aromatic polyester, etc. can be used.

Specific examples of crystalline thermoplastic polyesters include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, polybutylene naphthalate, poly-1,4-cyclohexylenedimethylene terephthalate, and polyethylene-1,2. - crystallinity of bis(phenoxy)ethane-4,4'-dicarboxylate, polyethylene isophthalate/terephthalate, polybutylene terephthalate/isophthalate, polybutylene terephthalate/decanedicarboxylate, polycyclohexanedimethylene terephthalate/isophthalate, etc. Copolyester and the like can be mentioned. Among them, it is preferable to use polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, polybutylene naphthalate, poly-1,4-cyclohexylenedimethylene terephthalate and the like. The content of the thermoplastic polyester resin (H1) in the polycarbonate resin composition is preferably 0 to 60% by weight, more preferably 0 to 50% by weight, from the viewpoint of improving the appearance of the injection foam molded article. more preferably 0 to 40% by weight.

<Polyester-polyether copolymer (H2)>
The polyester-polyether copolymer (H2) preferably contains aromatic polyester units and polyether units. The polyether unit is, for example, those represented by the following general formula (1), general formula (2), general formula (3), general formula (4), general formula (5) and general formula (6) mentioned. Among these, those represented by the following general formula (6) are preferable.

In the general formula (1), -A- is -O-, -S-, -SO-, -SO ₂ -, -CO-, an alkylene group having 1 to 20 carbon atoms, or an alkylene group having 6 to 20 carbon atoms. It is an alkylidene group. R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are each a hydrogen atom, a halogen atom or a monovalent hydrocarbon group having 1 to 5 carbon atoms. R ⁹ and R ¹⁰ are each a divalent hydrocarbon group having 1 to 5 carbon atoms. m and n represent the number of repeating oxyalkylene units, m and n are each an integer of 0 to 70 and 10≦m+n≦70. Each of m and n is preferably an integer of 0-50. More preferably, m is an integer of 2-70.

In formula (2), R ¹ , R ² , R ³ and R ⁴ each represent a hydrogen atom, a halogen atom or a monovalent hydrocarbon group having 1 to 5 carbon atoms. R ⁹ and R ¹⁰ are each a divalent hydrocarbon group having 1 to 5 carbon atoms. m and n represent the number of repeating oxyalkylene units, m and n are each an integer of 0 to 70 and 10≦m+n≦70. Each of m and n is preferably an integer of 0-50. More preferably, m is an integer of 2-70.

In the general formula (3), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each a hydrogen atom, a halogen atom or a monovalent hydrocarbon group having 1 to 5 carbon atoms. be. R ⁹ and R ¹⁰ are each a divalent hydrocarbon group having 1 to 5 carbon atoms. m and n represent the number of repeating oxyalkylene units, m and n are each an integer of 0 to 70 and 10≦m+n≦70. Each of m and n is preferably an integer of 0-50. More preferably, m is an integer of 2-70.

In general formula (4), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ are each a hydrogen atom, a halogen atom, or one having 1 to 5 carbon atoms. is a valent hydrocarbon group. R ⁹ and R ¹⁰ are each a divalent hydrocarbon group having 1 to 5 carbon atoms. m and n represent the number of repeating oxyalkylene units, m and n are each an integer of 0 to 70 and 10≦m+n≦70. Each of m and n is preferably an integer of 0-50. More preferably, m is an integer of 2-70.

In general formula (5), R ⁹ is a divalent hydrocarbon group having 1 to 5 carbon atoms. m represents the number of repeating oxyalkylene units, and m is an integer of 2-70.

In the general formula (6), m and n represent the number of repeating oxyalkylene units, m and n are integers of 0 to 50 and 10≦m+n≦50.

The aromatic polyester unit is an alternating polycondensate composed of an aromatic dicarboxylic acid or an aromatic dicarboxylic acid ester and a diol. Examples of the aromatic polyester unit include polyalkylene terephthalate units such as polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate; polyalkylene naphthalate units such as polyethylene naphthalate, polypropylene naphthalate and polybutylene naphthalate. Among these, polyalkylene terephthalate units are preferred, and polyethylene terephthalate units are more preferred. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, diphenyldicarboxylic acid, and diphenoxyethanedicarboxylic acid. Among them, terephthalic acid is preferred. Examples of the aromatic dicarboxylic acid esters include dialkyl esters of the aromatic dicarboxylic acids. In addition to aromatic dicarboxylic acids, other aromatic oxycarboxylic acids such as oxybenzoic acid, and aliphatic or alicyclic dicarboxylic acids such as adipic acid, sebacic acid, and cyclohexane 1,4-dicarboxylic acid may be used in combination. may The diol is, for example, a glycol having 2 to 10 carbon atoms such as ethylene glycol, trimethylene glycol, tetramethylene glycol, hexanediol, decanediol, cyclohexanedimethanol. From the viewpoint of the impact resistance, chemical resistance, and molding processability of the resulting molded product, the solution viscosity of the aromatic polyester in a phenol/tetrachloroethane = 1/1 (weight ratio) mixed solvent at 25 ° C. The logarithmic viscosity (IV value) at 0.5 g/dl is preferably 0.3 or more and 1.0 or less.

The method for producing the polyester-polyether copolymer (H2) is not particularly limited, but (1) a direct esterification method in which an aromatic dicarboxylic acid, a diol, and a polyether are reacted, (2) a dialkyl aromatic dicarboxylate (3) a method of polycondensing by adding a modified polyether during or after the transesterification of the aromatic dicarboxylic acid dialkyl ester and the diol, and (4) ) A high-molecular-weight aromatic polyester is used, and after mixing with a polyether, transesterification is performed under reduced pressure to melt.

The content of the polyester-polyether copolymer (H2) in the polycarbonate-based resin composition is preferably 0 to 60% by weight, more preferably 0 to 50% by weight, from the viewpoint of improving the appearance of the injection foam molded article. %, more preferably 0 to 40% by weight.

<Acrylonitrile-butadiene-styrene copolymer (H3)>
Acrylonitrile - butadiene - styrene copolymer, from the viewpoint of improving the appearance and maintaining heat resistance, preferably 0 to 50% by weight in 100% by weight of the polycarbonate resin composition, more preferably 0 to 40% by weight, and a more preferred range is 0 to 30% by weight.

The content of butadiene in the acrylonitrile-butadiene-styrene copolymer may be 10 to 30% by weight.

As an acrylonitrile-butadiene-styrene copolymer, part of the styrene in the acrylonitrile-butadiene-styrene copolymer is replaced with α-methylstyrene to improve the heat resistance of the usual acrylonitrile-butadiene-styrene copolymer. Further, acrylonitrile-butadiene-styrene copolymer modified with phenylmaleimide, which is further improved in heat resistance, can be used as appropriate.

The polycarbonate-based resin composition contains 1 to 15% by weight of the masterbatch (C) and 30% of the polycarbonate-based resin (G) from the viewpoint of effectively suppressing whitening of the surface of the injection foam molded article and improving the appearance. up to 99% by weight, as well as polyester resins, polyester-polyether copolymers, acrylonitrile-butadiene-styrene copolymers, acrylonitrile-ethylene-propylene-diene-styrene copolymers, acrylate-styrene-acrylonitrile copolymers, acrylonitrile - It is preferable to contain 0 to 55% by weight of one or more thermoplastic resins selected from the group consisting of styrene copolymers, polyarylate resins, polystyrene resins, and polyamide resins.

<Inorganic compound (J)>
In order to improve the flexural rigidity and dimensional stability of the injection foam molded article, the polycarbonate resin composition may further contain an inorganic compound (J). The inorganic compound is selected from the group consisting of mica, talc, montmorillonite, sericite, kaolin, glass flakes, tabular alumina, synthetic hydrotalcite, wollastonite, hollow glass balloons, carbon fibers, aramid fibers, and whiskers. One or more types are preferable, and from the viewpoint of the effect of improving bending rigidity and dispersibility in polycarbonate resin, one selected from the group consisting of mica, talc, montmorillonite, sericite, kaolin, glass flakes, hollow glass beads, and carbon fibers More preferably, at least one selected from the group consisting of mica, talc, glass flakes, and wollastonite, from the viewpoint of the balance of impact resistance, fluidity, and product appearance.

The content of the inorganic compound (J) is preferably 5% by weight or more and 45% by weight or less, more preferably 5% by weight or more and 35% by weight, in terms of impact resistance, heat resistance, rigidity, moldability, etc. % or less, more preferably 5 wt % or more and 25 wt % or less.

<Impact modifier (K)>
In order to further improve the impact resistance of the injection foam molded article, the polycarbonate resin composition may further contain an impact modifier. As the impact modifier, one or more selected from the group consisting of multi-stage graft polymers, polyolefin polymers, olefin-unsaturated carboxylic acid ester copolymers, and thermoplastic polyester elastomers are preferred.

The multi-stage graft polymer is obtained by graft-polymerizing a vinyl-based monomer to a rubber-like polymer. The rubber-like polymer preferably has a glass transition temperature of 0° C. or lower, more preferably -40° C. or lower. Specific examples of such rubber-like polymers include diene rubbers such as polybutadiene, butadiene-styrene copolymers, butadiene-acrylate copolymers, butadiene-acrylonitrile copolymers, polybutyl acrylate, poly Acrylic rubber such as 2-ethylhexyl acrylate, dimethylsiloxane-butyl acrylate rubber, silicone/butyl acrylate composite rubber, olefin rubber such as ethylene-propylene copolymer, ethylene-propylene-diene copolymer, polydimethyl Examples include siloxane rubber, dimethylsiloxane-diphenylsiloxane copolymer rubber, and the like. Examples of butadiene-acrylic acid ester copolymers include butadiene-butyl acrylate copolymers and butadiene-2-ethylhexyl acrylate copolymers. Polybutadiene, butadiene-styrene copolymer, and butadiene-butyl acrylate copolymer are preferably used in terms of impact resistance. Among butadiene-butyl acrylate copolymers, copolymers of 50 to 70% by weight of butyl acrylate and 30 to 50% by weight of butadiene are preferred from the standpoint of weather resistance and impact resistance. The average particle size of the rubber-like polymer is also not particularly limited, but is preferably in the range of 0.05 µm or more and 2.00 µm or less, more preferably 0.1 µm or more and 0.4 µm or less. The gel content is also not particularly limited, but is preferably in the range of 10% to 99% by weight, more preferably 80% to 96% by weight.

Examples of vinyl monomers used for producing the multistage graft polymer include aromatic vinyl monomers, vinyl cyanide monomers, and (meth)acrylic acid esters. These may be used individually by 1 type, and may be used together 2 or more types. As the aromatic vinyl monomer, the vinyl cyanide monomer, and the (meth)acrylic acid ester, those listed in the explanation of the acrylic resin particles (a) can be appropriately used.

Specifically, the multi-stage graft polymer is one or more rubber-like polymers selected from the group consisting of polybutadiene, butadiene-styrene copolymer, butadiene-acrylate copolymer, and polyorganosiloxane. Polymerizing 90% by weight of one or more vinyl-based monomers selected from the group consisting of aromatic vinyl monomers, vinyl cyanide monomers, and (meth)acrylic acid ester compounds in the presence of the rubber-like polymer. It is preferably composed of 10 to 90% by weight of the graft component composed of the polymer obtained by the above. It is particularly preferred to use a multi-stage graft polymer produced using an organophosphorus emulsifier.

When a core/shell graft polymer is prepared as the multi-stage graft polymer, and the total amount of the rubber-like polymer and the vinyl-based monomer is 100% by weight, the rubber-like polymer is 10% by weight or more and 90% by weight or less, and the vinyl The content of the system monomer is preferably 10% to 90% by weight, more preferably 30% to 85% by weight of the rubber-like polymer, and 15% to 70% by weight of the vinyl type monomer. If the ratio of the rubber-like polymer is less than 10% by weight, the impact resistance tends to decrease, while if it exceeds 90% by weight, the heat resistance tends to decrease.

The amount of the impact modifier is preferably 0 to 20% by weight, preferably 0 to 15% by weight, in the polycarbonate resin composition from the viewpoint of impact resistance, heat resistance, rigidity and moldability. more preferably 0 to 10% by weight.

The polycarbonate-based resin composition may contain additives such as a flame retardant, an anti-UV agent, a stabilizer, a release agent, a pigment, a softener, a plasticizer, and a surfactant, if necessary.

<Injection foam molding>
By injection-foaming the polycarbonate-based resin composition, whitening is suppressed, and an injection-foamed article having a good appearance can be obtained. Specifically, the injection foam molded article can be produced by a method of foaming the polycarbonate-based resin composition in a mold. There are various methods of foaming in a mold. A so-called core-back method (moving cavity method) is preferred, in which a mold is used, and after injection of the resin composition to the initial filling thickness is completed, the movable mold is retracted to foam. According to the core-back method, by forming a non-foamed layer on the surface, unevenness on the order of several μm to several tens of μm in appearance is smoothed, and the internal foamed layer easily becomes uniform fine cells, resulting in excellent lightness. It is preferable because it is easy to obtain an injection foamed molded product.

In the core-back method, the retraction of the movable die may be performed in one stage or in multiple stages of two or more stages, and the retraction speed may be adjusted as appropriate. For example, a process of injecting and filling a mold composed of a fixed mold and a movable mold that can move forward and backward to any position and having an initial cavity clearance t ₀ (initial filling thickness) of 1.5 mm or more and 2.7 mm or less. and, after completion of injection filling to the initial filling thickness, the step of foaming by retracting the movable mold so that the cavity clearance t _f after core-back is 2.0 mm or more and 6.0 mm or less is preferably included.

In the core-back method, other molding conditions include a resin temperature of 240° C. to 280° C., a mold temperature of 60° C. to 90° C., a molding cycle of 1 second to 60 seconds, and an injection speed of 10 mm/second to 400 mm/second. , an injection pressure of 10 MPa or more and 200 MPa or less, a back pressure of 5 MPa or more and 40 MPa or less, and a screw rotation speed of 10 rpm or more and 200 rpm or less.

The injection foam molded article can be suitably used for applications such as electrical appliances such as mobile phones and personal computer housings; vehicle members such as automobile fenders, door panels, back door panels, garnishes, pillars, and spoilers.

The specific gravity of the injection foam molded product is preferably 0.3 g/cm ³ or more and 1.2 g/cm ³ or less from the viewpoint of weight reduction and impact strength of the molded product. If the specific gravity of the injection foam molded product is less than 0.3 g/cm ^{3 ,} the number of large cells exceeding 1.5 mm tends to increase and the impact strength tends to decrease. Hateful. The specific gravity can be calculated by the water substitution method in accordance with JIS K 7112:1999. From the viewpoint of weight reduction and impact strength, the expansion ratio of the injection foam molded product is preferably 1.1 times or more and 3.0 times or less, more preferably 1.1 times or more and 2.5 times or less, and 1.1 times or more. 2.0 times or less is more preferable. When the expansion ratio is less than 1.1 times, it tends to be difficult to obtain lightness, and when it exceeds 3.0 times, the decrease in surface impact strength tends to be significant. In the present specification, the expansion ratio is a value obtained by dividing the thickness of the injection foam molded article (cavity clearance t _f after core-back) by the initial cavity clearance t ₀ .

EXAMPLES The present invention will be described below based on specific examples and comparative examples, but the present invention is not limited to the following examples. In the following, unless otherwise indicated, "parts" means parts by weight and "%" means % by weight.

Various measurement methods and evaluation methods are shown below.

(1) Glass transition temperature Acrylic resin particles (a) (suspension polymer particles) and carrier resin (B) were measured at 5°C/min using a differential scanning calorimeter (DSC220C manufactured by Seiko Electronics Industry Co., Ltd.). The glass transition temperature was measured under elevated temperature conditions.
(2) Vicat Softening Temperature The Vicat softening temperature of the acrylic resin particles (b) (emulsion polymer particles) was measured according to JIS K7206 A method. The test piece was produced by recovering an emulsion polymer obtained by emulsion polymerization by coagulation, heat treatment and drying, pelletizing with an extruder, and sheeting with a press molding machine.
(3) Average Particle Size The average particle sizes of the acrylic resin particles (a), the acrylic resin particles (b) and the carrier resin (B1) were measured with Microtrac MT-3300 manufactured by Microtrac Bell Co., Ltd. The average particle size (unexpanded) of the thermally expandable microcapsules (A) was measured with a particle size distribution analyzer SALD-3000J manufactured by Shimadzu Corporation.
(4) Weight Average Molecular Weight The weight average molecular weight of the resin was measured by GPC (gel permeation chromatography). Specifically, measurement was performed using a system: HLC-8220 manufactured by Tosoh Corporation, a column: TSKgel SuperHZM-H manufactured by Tosoh Corporation (x 2), and a solvent: THF, and a value calculated in terms of polystyrene was used.
(5) Compatibility with polycarbonate-based resin (PC) Differential scanning calorimetry (DSC) is performed on a mixture of the carrier resin composition (B) and polycarbonate-based resin, and the presence or absence of compatibility with PC is determined according to the following criteria. did.
Compatible: One glass transition temperature peak in DSC No compatibility: Two glass transition temperature peaks in DSC (6) Shear viscosity Carrier resin composition or carrier resin at 80 ° C. The shear viscosity was measured using a flow tester "model CFT-500C" manufactured by Shimadzu Corporation. Specifically, the measurement start temperature is set to 50° C., the carrier resin composition or carrier resin is allowed to flow in a capillary having a diameter of 1.0 mm and a length of 10 mm under a constant load of 30 kgf, and the temperature is raised at a rate of 10° C./min. , and the shear viscosity was measured when the measurement temperature reached 80°C.
(7) Viscosity The viscosity of the plasticizer (B2) at 25° C. was measured using an E-type viscometer according to JIS Z 8803-1991.
(8) Maximum expansion temperature "TMA measurement" was performed using TMA-7 type manufactured by Birkin Elmer. About 0.25 mg of the sample is put in a container, the temperature is raised at a temperature increase rate of 5 ° C./min, and the height displacement is continuously measured. was taken as the maximum expansion temperature.
(9) Processability of masterbatch The cross section of the masterbatch pellet is observed with a scanning electron microscope (SEM, manufactured by JEOL Ltd., model "JSM-6060LA"), and based on the state of the thermally expandable microcapsules, The workability of the masterbatch was evaluated.
Good: no expansion of thermally expandable microcapsules Poor: expansion of thermally expandable _{microcapsules} (10) Expansion ratio of injection foam molded product It was calculated by dividing by the cavity clearance t ₀ in the clamped state of the mold at the relevant portion.
(11) Appearance of injection foam molded article The surface of the flat plate-shaped injection foam molded article was visually observed to evaluate the appearance.
Good: No whitening Slightly good: Slight whitening Poor: Significant whitening

<Production Example 1 of Carrier Resin Particles (B)>
<Production of acrylic resin particles (a)>
A reactor equipped with a stirrer was charged with 220 parts of deionized water and 15 parts of a 3%-PVA aqueous solution (GH-20: manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), and the inside of the reactor was replaced with nitrogen. A monomer mixture of 25 parts of butyl acrylate and 75 parts of methyl methacrylate in which 0.5 parts of lauroyl peroxide, 0.5 parts of benzoyl peroxide, and 0.2 parts of 2-ethylhexyl thioglycolate are dissolved is added thereto, The rotational speed of the stirrer was adjusted so that the dispersed particle diameter of the monomer was about 250 μm. Thereafter, the temperature was raised stepwise to 60° C. for 2 hours, 70° C. for 2 hours, 80° C. for 2 hours, and 90° C. for 1 hour to complete the polymerization, and acrylic resin particles (a) (polymer solid content) were obtained. A suspension of acrylic resin particles (a) having a concentration of 30%, a glass transition temperature of 72° C., and an average particle size of 150 μm was prepared.

<Production of acrylic resin particles (b)>
220 parts of deionized water, 0.3 parts of boric acid, 0.03 parts of sodium carbonate, 0.09 parts of sodium N-lauroyl sarcosinate, 0.09 parts of sodium formaldehyde sulfoxylate, 0.09 parts of sodium formaldehyde sulfoxylate, sodium ethylenediaminetetraacetate were added to a reactor provided with a stirrer. 0.006 parts of ferrous sulfate heptahydrate and 0.002 parts of ferrous sulfate heptahydrate were charged, and after purging with nitrogen, the temperature was raised to 80°C. 25% of a monomer mixture comprising 0.1 part of hydroperoxide was charged at once and polymerized for 45 minutes. The remaining 75% of this mixture was then added continuously over 1 hour. After completion of the addition, the temperature was maintained for 2 hours to complete the polymerization. During this time, 0.2 parts by weight of sodium N-lauroyl sarcosinate was added. The average particle diameter of the polymer particles in the obtained innermost layer crosslinked methacrylic polymer latex was 1600 Å (determined using light scattering at a wavelength of 546 nm), and the polymerization conversion rate (amount of polymer produced/monomer Charge x100) was 98%. Subsequently, the obtained innermost layer crosslinked methacrylic polymer latex was kept at 80° C. in a nitrogen stream, and after adding 0.1 parts by weight of potassium persulfate, 41 parts by weight of n-butyl acrylate and 9 parts by weight of styrene were added. and 1 part by weight of allyl methacrylate were continuously added over 5 hours. During this time, 0.1 part by weight of potassium oleate was added in three portions. After the completion of addition of the monomer mixed solution, 0.05 parts by weight of potassium persulfate was further added and kept for 2 hours in order to complete the polymerization. In the resulting emulsion-polymerized latex, the latex particles (b1) had an average particle size of 2300 Å and a polymerization conversion rate of 99%. Subsequently, the latex of the latex particles (b1) was kept at 80° C., and after adding 0.02 parts by weight of potassium persulfate, 24 parts by weight of methyl methacrylate, 1 part by weight of n-butyl acrylate, and 0 parts by weight of t-dodecyl mercaptan. .1 part by weight of the mixture was added continuously over 1 hour. After completion of addition of the monomer mixture, the mixture was held for 1 hour to obtain a latex of an emulsion-polymerized graft copolymer (acrylic resin particles (b)) having a multilayer structure, an average particle size of 0.25 µm, and a Vicat softening temperature of 90°C. rice field.

<Production of carrier resin (B1)>
96 parts of the obtained latex of acrylic resin particles (b) (solid content, i.e., 30 parts of acrylic resin particles (b)) and 332 parts of suspension of acrylic resin particles (a) (solid content, i.e., acrylic resin Particles (a) 100 parts) were mixed with stirring, and the resulting mixed suspension (solid content, that is, total concentration of acrylic resin particles (a) and acrylic resin particles (b): 30%) was heated to 60 ° C. After adjustment, 50 parts of a 1.0% aqueous calcium chloride solution was added dropwise over 10 minutes while stirring. Thereafter, the temperature was raised to 95° C. with stirring and heat treatment was performed to obtain a carrier resin (B1-1) having an average particle size of 180 μm. The carrier resin (B1-1) had a weight average molecular weight of 280,000 and a glass transition temperature (Tg) of 77°C.

<Production Example 2 of Carrier Resin (B1)>
A carrier resin (B1-2) was produced in the same manner as in Production Example 1, except that 0.5 parts of 2-ethylhexyl thioglycolate was used in the production of the acrylic resin particles (a). The obtained carrier resin (B1-2) had an average particle diameter of 200 μm, a weight average molecular weight of 60,000, and a glass transition temperature (Tg) of 77°C.

<Production Example 3 of Carrier Resin (B1)>
A carrier resin (B1-3) was produced in the same manner as in Production Example 1, except that 2-ethylhexyl thioglycolate was changed to 1.5 parts in the production of the acrylic resin particles (a). The obtained carrier resin (B1-3) had an average particle diameter of 190 μm, a weight average molecular weight of 20,000, and a glass transition temperature (Tg) of 77°C.

<Production Example 4 of Carrier Resin (B1)>
A carrier resin (B1-4) was prepared in the same manner as in Production Example 1, except that 2-ethylhexyl thioglycolate was changed to 0.3 parts. The obtained carrier resin (B1-4) had an average particle diameter of 200 μm, a weight average molecular weight of 110,000, and a glass transition temperature (Tg) of 76°C.

<Production Example 1 of polyester-polyether copolymer>
A reactor equipped with a stirrer and a gas discharge outlet was charged with polyethylene terephthalate (IV=0.65) produced with a germanium-based catalyst and bisphenol A ethylene oxide 30 mol adduct (manufactured by Toho Chemical Co., Ltd., "Bisol 30EN", general Corresponding to the polyether unit represented by the formula (6), n + m is 30.), 400 ppm of germanium dioxide, a stabilizer ( 2000 ppm of Irganox 1010) manufactured by Ciba Specialty Chemicals Co., Ltd. was charged, held at 270° C. for 2 hours, depressurized with a vacuum pump, polycondensation was performed at 1 torr, and depressurization was terminated when a predetermined polymerization degree was reached. After stopping the reaction and taking out the manufactured product, the strand cooled in a water tank is subjected to post-crystallization and drying at the same time in a hot air dryer set at 100 ° C., then put into a grinder and pelleted. A polyester-polyether copolymer (H2) in the form of pellets was obtained. The resulting polyester-polyether copolymer (H2) had a polyether content of 30% by weight and an IV value of 0.45. The IV value of polyethylene terephthalate and polyester-polyether copolymer is calculated from the logarithmic viscosity at 0.5 g/dl at 25°C in a mixed solvent of tetrachloroethane/phenol = 50/50 (weight ratio). is.

(Example 1)
<Preparation of masterbatch of thermally expandable microcapsules>
Carrier resin (B1-1) obtained above, acrylic plasticizer (B2-1) as plasticizer (B2) (manufactured by Toagosei Co., Ltd., "ALPHON UP1020", weight average molecular weight 2000, viscosity at 25 ° C. 500 mPa · s, all acrylic, non-functional group) and thermally expandable microcapsules (A) ("Microsphere S2640D" manufactured by Kureha Co., Ltd., average particle size 21 µm, maximum expansion temperature 249 ° C.) are shown in Table 1 below. After mixing at a weight ratio, set in a gravimetric feeder, supply to a co-meshing twin-screw extruder (manufactured by Technobel, 25 mm extruder), melt-knead at 130 ° C., water-cool the strand, and cut with a pelletizer. to obtain a masterbatch (C-1) of thermally expandable microcapsules in the form of pellets.

<Preparation of Polycarbonate Resin Composition>
Polycarbonate resin (manufactured by Mitsubishi Chemical Corporation "S-2000", number average molecular weight 23,000) 50 parts, thermoplastic polyester resin (manufactured by Bell Polyester Products Co., Ltd. "Belpet EFG70", polyethylene terephthalate) 15 parts , 15 parts of the polyester-polyether copolymer (H2) obtained above and 15 parts of an inorganic compound (mica, "YM-21S" manufactured by Yamaguchi Mica Co., Ltd., number average particle size 27 μm) were mixed in the same direction and meshed biaxially. The mixture was supplied to an extruder (TEX44, manufactured by Japan Steel Works, Ltd.), melt-kneaded at 280° C., cooled with water, and cut with a pelletizer to obtain a polycarbonate-based resin composition as a pellet-shaped base component. Polycarbonate resin composition ( I-1) was obtained.

<Preparation of injection foam molding>
The polycarbonate-based resin composition obtained above was subjected to injection foam molding to prepare an injection foam molded product. Specifically, the polycarbonate resin composition (I-1) is supplied to an electric injection molding machine (manufactured by Toyo Machinery & Metal Co., Ltd.) having a core-back function and a shut-off nozzle with a mold clamping force of 180 t, and the cylinder is After melt-kneading at a temperature of 270 ° C. and a back pressure of 10 MPa, a cavity ( Injection filling was performed at an injection speed of 100 mm/sec into a mold having an initial cavity clearance of t ₀ =2.4 mm and a φ8 mm direct gate at the center of the bottom. To the initial filling thickness (initial cavity clearance t ₀ ) After completion of injection filling, the bottom part has a desired thickness (expansion ratio) (so that the cavity clearance t _f after core back is 3.6 mm) Movable mold was retracted to foam the polycarbonate-based resin composition in the cavity. After cooling for 40 seconds after completion of foaming, the injection foam molded article was taken out.

(Example 2)
A thermally expandable microcapsule masterbatch (C-2) and a polycarbonate resin composition were prepared in the same manner as in Example 1, except that the carrier resin (B1-2) was used instead of the carrier resin (B1-1). (I-2) and an injection foam molded product were produced.

(Example 3)
Carrier resin (B1-2) was used instead of carrier resin (B1-1), and the weight ratio of carrier resin (B1-2) and acrylic plasticizer (B2) was changed as shown in Table 1. , in the same manner as in Example 1, a masterbatch (C-3) of thermally expandable microcapsules, a polycarbonate-based resin composition (I-3) and an injection foam molded product were produced.

(Example 4)
A thermally expandable microcapsule masterbatch (C-4) and a polycarbonate resin composition were prepared in the same manner as in Example 1, except that the carrier resin (B1-3) was used instead of the carrier resin (B1-1). (I-4) and an injection foam molded product were produced.

(Example 5)
Carrier resin (B1-3) was used instead of carrier resin (B1-1), and the weight ratio of carrier resin (B1-3) and acrylic plasticizer (B2) was changed as shown in Table 1. In the same manner as in Example 1, a thermally expandable microcapsule masterbatch (C-5), a polycarbonate resin composition (I-5) and an injection foam molded product were produced.

(Example 6)
Acrylic plasticizer (B2-2) (manufactured by Toagosei Co., Ltd., "Alphon UP1500", weight average molecular weight 12,000, viscosity at 25 ° C. 80,000 mPa s, styrene acrylic, no functional group) is used as a plasticizer. A thermally expandable microcapsule masterbatch (C-6), a polycarbonate-based resin composition (I-6) and an injection foam molded product were produced in the same manner as in Example 5 except that

(Example 7)
A thermally expandable microcapsule masterbatch (C-7) and a polycarbonate resin composition were prepared in the same manner as in Example 6, except that the carrier resin (B1-4) was used instead of the carrier resin (B1-3). (I-7) and an injection foam molded product were produced.

(Comparative example 1)
A master of thermally expandable microcapsules was prepared in the same manner as in Example 1, except that the weight ratio of the carrier resin (B1-1) was changed as shown in Table 1 and the acrylic plasticizer (B2) was not used. A batch, a polycarbonate-based resin composition, and an injection foam molded article were produced.

(Comparative example 2)
Thermal expansion was performed in the same manner as in Comparative Example 1, except that an acrylic processing aid ("Kane Ace PA60" manufactured by Kaneka Co., Ltd., weight average molecular weight 5,000,000) was used instead of the carrier resin (B1-1). A masterbatch of polycrystalline microcapsules, a polycarbonate-based resin composition, and an injection foam molded product were prepared.

The processability of the masterbatches of Examples and Comparative Examples was evaluated as described above, and the results are shown in Table 1 below. In addition, the appearance of the injection foam molded articles of Examples and Comparative Examples was evaluated as described above, and the results are shown in Table 1 below. Table 1 also shows the expansion ratio.

As can be seen from Table 1 above, the carrier resin (B1), which is an acrylic resin having a weight average molecular weight of 8,000 to 350,000, and the acrylic plasticizer (B2) having a weight average molecular weight of 1,000 to 20,000 are included. In the examples using the carrier resin composition (B), which is substantially compatible with the polycarbonate resin and has a shear viscosity at 80° C. of 1.0 Pa·s or more and 1.5×10 ⁶ Pa·s or less, , The processability of the masterbatch of the thermally expandable microcapsules is good, and the surface of the injection foamed product obtained by injection foaming the polycarbonate resin composition using the masterbatch does not whiten, and the appearance is good. was good.

On the other hand, the acrylic plasticizer (B2) having a weight average molecular weight of 1,000 or more and 20,000 or less is not used, and is substantially compatible with the polycarbonate resin, but the shear viscosity at 80 ° C. is 1.5 × In Comparative Example 1 using an acrylic resin exceeding 10 ⁶ Pa·s, the processability of the masterbatch of thermally expandable microcapsules was poor, and the polycarbonate resin composition using the masterbatch was injection-foam-molded. Whitening occurred remarkably on the surface of the foam molded article, and the appearance was poor. On the other hand, the acrylic plasticizer (B2) having a weight average molecular weight of 1,000 or more and 20,000 or less is not used, is not substantially compatible with the polycarbonate resin, and has a shear viscosity of 1 at 80 ° C. Even in Comparative Example 2 using an acrylic resin exceeding 5×10 ⁶ Pa·s, the processability of the masterbatch of thermally expandable microcapsules was poor, and the polycarbonate resin composition using the masterbatch was not foamed by injection. The surface of the molded injection foamed product was noticeably whitened, and the appearance was poor.

Claims (18)

A masterbatch (C) containing a thermally expandable microcapsule (A) and a carrier resin composition (B),
The carrier resin composition (B) contains a carrier resin (B1) and a plasticizer (B2), and the carrier resin (B1) has a weight average molecular weight of 8,000 or more and 350,000 or less and is solid at 20°C. It is an acrylic resin, the plasticizer (B2) is liquid at 20° C., and has a weight average molecular weight of 1,000 or more and 20,000 or less,
The carrier resin composition (B) is characterized by being substantially compatible with the polycarbonate-based resin and having a shear viscosity at 80° C. of 1.0 Pa·s or more and 1.5×10 ⁶ Pa·s or less. ,Master Badge. The masterbatch according to claim 1, wherein the masterbatch (C) is for a polycarbonate resin. The polycarbonate-based resin further includes a polyester-based resin, a polyester-polyether copolymer, an acrylonitrile-butadiene-styrene copolymer, an acrylonitrile-ethylene-propylene-diene-styrene copolymer, an acrylate-styrene-acrylonitrile copolymer, 3. The masterbatch according to claim 1, which contains one or more other thermoplastic resins selected from the group consisting of acrylonitrile-styrene copolymers, polyarylate resins, polystyrene resins, and polyamide resins. The masterbatch according to any one of claims 1 to 3, wherein the plasticizer (B2) is an acrylic plasticizer. The masterbatch according to any one of claims 1 to 4, wherein the carrier resin (B1) has a glass transition temperature (Tg) of -30°C or higher and 150°C or lower. The thermally expandable microcapsules (A) have a core-shell structure and are composed of a core composed of one or more compounds having a boiling point of 10° C. or higher and 330° C. or lower, and a shell enclosing the core. ,
The shell includes a nitrile-based monomer, a (meth)acrylate-based monomer, an aromatic vinyl-based monomer, a diene-based monomer, a vinyl-based monomer having a carboxyl group, a methylol group, a hydroxyl group, an amino A resin having structural units derived from one or more monomers selected from the group consisting of monomers having one or more reactive functional groups selected from the group consisting of groups consisting of groups, epoxy groups, and isocyanate groups. The masterbatch according to any one of claims 1 to 5, which is composed of. The masterbatch according to any one of claims 1 to 6, wherein the thermally expandable microcapsules (A) have a maximum expansion temperature of 180°C or higher and 300°C or lower. In the resin constituting the shell, the concentration of structural units derived from one or more monomers selected from the group consisting of a monomer containing a carboxyl group and a monomer containing an amino group is 12 mmol/g. 8. The masterbatch according to claim 6 or 7, which is The masterbatch according to any one of claims 1 to 8, wherein the thermally expandable microcapsules (A) have an average particle size of 0.5 µm or more and 50 µm or less. The carrier resin (B1) comprises acrylic resin particles (a) having an average particle size of 50 μm to 500 μm and an average particle size covering the acrylic resin particles (a) of 0.05 μm to 0.5 μm. The masterbatch according to any one of claims 1 to 9, which is an acrylic resin containing the acrylic resin particles (b) of The masterbatch according to claim 10, wherein the acrylic resin particles (a) are composed of 30 to 100% by weight of (meth)acrylic acid ester and 0 to 70% by weight of a vinyl monomer copolymerizable therewith. . 12. The acrylic resin particles (b) according to claim 10 or 11, comprising 30 to 100% by weight of a (meth)acrylic acid ester and 0 to 70% by weight of a vinyl monomer copolymerizable therewith. Master Badge. The acrylic resin particles (b) contain 50 to 100% by weight of a (meth)acrylic acid ester, 0 to 40% by weight of an aromatic vinyl monomer, 0 to 10% by weight of a vinyl monomer copolymerizable therewith, and polyfunctional 50 to 90 parts by weight of latex particles (b1) containing 0 to 5% by weight of monomer, 10 to 100% by weight of (meth)acrylic acid ester, 0 to 90% by weight of aromatic vinyl monomer, and 0 to 25% by weight of vinyl cyanide monomer % and 10 to 50 parts by weight of a monomer mixture (b2) containing 0 to 20% by weight of a vinyl monomer copolymerizable therewith, the latex particles (b1) and the monomer mixture. The masterbatch according to any one of claims 10 to 12, wherein the sum of (b2) is 100 parts by weight. The masterbatch (C) contains 30% by weight or more and 80% by weight or less of the thermally expandable microcapsules (A), 15% by weight or more and 65% by weight or less of the carrier resin (B1), and the plasticizer (B2). 5% by weight or more and 30% by weight or less, and the content of the carrier resin (B1) is greater than the content of the plasticizer (B2). The masterbatch according to any one of claims 1 to 13. 1 to 15% by weight of the masterbatch according to any one of claims 1 to 14, 30 to 99% by weight of polycarbonate resin, and polyester resin, polyester-polyether copolymer, acrylonitrile-butadiene-styrene selected from the group consisting of copolymers, acrylonitrile-ethylene-propylene-diene-styrene copolymers, acrylate-styrene-acrylonitrile copolymers, acrylonitrile-styrene copolymers, polyarylate resins, polystyrene resins, and polyamide resins A polycarbonate-based resin composition containing 0 to 55% by weight of one or more other thermoplastic resins. The polycarbonate-based resin composition according to claim 15, further comprising an inorganic compound. 17. An injection foam-molded article obtained by subjecting the polycarbonate resin composition according to claim 15 or 16 to injection foam molding. 17. A method for producing an injection foam-molded article, comprising supplying the polycarbonate-based resin composition according to claim 15 or 16 to an injection molding machine, filling the composition to an initial filling thickness, and then backing the core of the mold.

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